Selective enucleation (SE) was applied to germinal vesicle (GV) oocytes by removing the chromatin attached to nuclear envelope, and leaving the liquid contents of GV in the cytoplast. However, after reconstruction with 1/8 blastomeres or fetal fibroblasts (FFs) neither the maturation efficiency nor the frequency of normal (asymmetric) division was improved as compared with completely enucleated (CE) oocytes. Chromosomal aberrations introduced with somatic nuclei were not rescued in SE oocytes either. On the other hand, timing of maturation division in SE GV oocytes, but not in CE GV oocytes, reconstructed with GV-karyoplasts was like in the control. After maturation and fertilization in vitro, SE oocytes reconstructed with 1/8 blastomeres developed nucleolated donor pronuclei, contrary to CE oocytes. The latter could be rescued with nucleoli-containing nucleus, but not anucleolate nucleus, from a 1/2 blastomere. SE oocytes reconstructed with FFs contained nucleolated pronuclei upon activation, unlike CE GV oocytes. These experiments show that the ooplast nucleolar material and/or embryonic nucleolus are indispensable for pronuclei formation. SE oocytes reconstructed with 1/8 blastomeres or FFs failed to cleave after activation or in vitro fertilization. Control GV oocytes enucleolated before fertilization seized cleavage at the 6-cell stage, as oppose to intact GV oocytes, which in 50.9% yielded morulae/blastocysts. These results suggest that ooplast nucleolar material is essential for the cleavage divisions. Activation of cumulus-enclosed SE GV oocytes matured in hormone-supplemented medium and fused to 1/2 blastomere-karyoplasts, yielded morulae, and blastocysts in 45.5% and 23.4% of reconstructed oocytes, respectively.

This study examined the effects of a dietary synbiotic supplement on the behavioral patterns and growth performance of broiler chickens exposed to heat stress (HS). Three hundred sixty 1-day-old male Ross 708 broiler chicks were distributed among 24 floor pens (15 chicks per pen); each pen was randomly assigned to one of 3 dietary treatments containing a synbiotic at 0 (control), 0.5 (0.5X) and 1.0 (1.0X) g/kg. From d 15 to 42, birds were exposed to HS at 32°C daily from 08:00 to 17:00. Five broiler chickens were randomly marked in each pen for behavioral observation. Instantaneous scan sampling was used to record the birds' behavioral patterns. Performance parameters were measured on d 7, 14, 28 and 42. The synbiotic fed birds exhibited more standing, sitting, walking, feeding, preening and less wing spreading and panting behaviors (P < 0.05) compared to birds fed the control diet. The synbiotic group also had higher BW, BW gain and feed intake on d 7, 14 and 42 (P < 0.05), and higher BW, feed intake and feed conversion ratio at d 28 (P < 0.01). There were no treatment effects on drinking behavior, BW gain on d 28 and feed conversion ratio on d 42 (P > 0.05). There were few dose-related differences of the synbiotic on production performance; namely, the 1.0X concentration resulted in the highest BW and feed intake on d 14 and 42 (P < 0.05), while BW gain was higher compared to the control group only on d 42 (P < 0.05). The results suggest that the synbiotic supplement may prove to be an important management tool for the broiler industry to diminish the negative effects of HS, potentially safeguarding the welfare and production of broiler chickens, particularly in areas that experience hot climates.

No abstract

No abstract